Various types of automatic music playing apparatuses are known in the art, with which musical tones are generated based on a musical performance data file to give an automatic musical performance. An example of such automatic music playing apparatuses is one which stores many data files of music pieces and automatically plays those music pieces successively. See Japanese patent No. 2,910,833. In such an automatic music playing apparatus, the order of the music pieces to be automatically played are previously set by the user or by default, and the music pieces are automatically played one after another accordingly. Some apparatuses further store lots of registration data (i.e. data setting various parameters for a performance) and play the music pieces by properly changing the apparatus setting of controlling the parameters for the performance, accordingly. See unexamined Japanese patent publication No. S62-187397. More particularly, a multiplicity of registration data sets, each set consisting of a combination of plural performance controlling parameters with respect to musical tone generation such as the timbre (voice) and the rhythm utilized in conducting a performance, are previously assigned to predetermined manipulating controls such as buttons and switches, so that the user will manipulate such a button or a switch to set the parameters in a lump and the apparatus will conduct an automatic playing of the music based on such set parameters. The order in which the registration data are utilized may be designated by the user's previous setting or by the default setting.
In a conventional automatic music playing apparatus as mentioned above, the automatic musical performance data and the registration data are stored in an external storage medium such as a semiconductor memory, and these data can be arbitrarily read out from the storage medium into the working memory to be used for playing music automatically. In such a conventional automatic music playing apparatus, however, when a plurality of music pieces are played automatically in a predetermined order of the music pieces, the automatic music playing data file for the music piece to be played next can be read out only after the currently playing music piece comes to an end. More specifically, it takes time to read out a data file of automatic playing of a music piece stored in an external storage device, and accordingly there will be unnecessary dead time between the end of playing a music piece and the start of playing the next music piece. Further, in case the order of the music pieces to be played are not previously set, the user has to designate a music piece to be played next properly during the automatic playing of the current music piece. Otherwise, the automatic successive playing of a plurality of music pieces will be interrupted inconveniently. On the other hand, with an automatic music playing apparatus which permits changes in registration during the automatic playing of a music piece, it will take time to read out a necessary registration data set from an external storage medium, even where plural registrations, i.e. plural sets or combinations of parameters, are previously set and assigned to the switches or the like according to the order of use, and thus it is hard to reflect a new registration to the playing immediately when it is intended. This is because the automatic performance data set and the registration data set are read out from the external storage medium every time and only when they are required, and the data sets which will be required later in the order of music pieces to be played or in the order of registrations to be used are not read out beforehand. Thus, the times required for reading out various necessary data sets from the external storage device will deteriorate the consecutive automatic music playing, which is a disadvantageous problem in the conventional apparatus.